A process for manufacturing a semiconductor device includes removing a film formed on a semiconductor wafer (hereinafter, simply referred to as “the wafer”) that is a to-be-processed substrate by etching with a chemical liquid. For example, a SiN film used as a hard mask is removed with hydrofluoric acid or a Si-based film is removed with ammonia or an ammonia-hydrogen peroxide solution (SC1).
If such a process is performed with a single wafer etching method, a chemical liquid is supplied to the wafer while rotating the wafer held by a spin chuck. However, in etching of a back surface of the wafer, a nozzle is installed within a hollow rotating shaft that extends downward from a center of the spin chuck and the chemical liquid is upwardly discharged from the nozzle, so that the discharged chemical liquid is expanded from the center of the back surface of the wafer to the circumference to perform the chemical-liquid processing (for example, see Japanese Laid-Open Patent Publication No. Hei 07-326569).
In the above-described etching processing with the chemical liquid, the etching rate increases using a high-temperature chemical liquid having a temperature of, for example, 50° C. or higher, higher than the room temperature for increasing processing throughput. However, as disclosed in Japanese Laid-Open Patent Publication No. Hei 07-326569, if the high-temperature chemical liquid is discharged to the center of the back surface of the wafer, the temperature of the chemical liquid is high at the center of the back surface of the wafer and decreases while the chemical liquid expands to the circumference of the wafer. Therefore, the etching amount increases at the center of the wafer and decreases at the circumference of the wafer, thereby incurring the low uniformity of the etching. In addition, as wafer size increases, such a low uniformity becomes more conspicuous.